In order to realize the game of chess, we must first understand the rules of chess, so as to facilitate our programming and understanding.
The rules are as follows:
On the Nine-palace chessboard, as long as the three pieces go in one line (horizontal, vertical, diagonal), the other side will lose.
First of all, our game program should have a menu page, which is used to let users choose to play the game. We can use functions to implement it. First, we build a game.h as a header file, and then define a game.c file to realize the specific functions (creating chessboard, initializing chessboard, etc.). Finally, a main.c file is defined to implement the game.

1.game.h (header file)

game.h(Header file)
#ifndef  __GAME_H__
#define __GAME_H__
#include<string.h>
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
void InitBoard(char board[][3],int row,int col);
void ShowBoard(char board[][3],int row,int col);
void PlayerMove(char board[][3],int row,int col);
char IsWin(char board[][3],int row,int col);
void ComputerMove(char board[][3],int row,int col);
#endif//__GAME_H__

2. main. C (main function)

#include "game.h"

void menu()
{
	printf("*********************\n");
	printf("*******1.play********\n");
	printf("*******0.exit*********\n");
	printf("*********************\n");
}
void game()
{
	char ret = 0;
	char board[3][3] = {0};
	InitBoard(board,3,3);
	ShowBoard(board,3,3);
	while(1)
	{
		PlayerMove(board,3,3);
		ret = IsWin(board,3,3);
		if(ret != ' ')
		{
			break;//Player wins or draws.
		}
		ShowBoard(board,3,3);
		
		ComputerMove(board,3,3);
		ret = IsWin(board,3,3);
		if(ret != ' ')
		{
			break;//The computer wins or draws.
		}
		ShowBoard(board,3,3);
	}
	if(ret == 'Q')
	{
		printf("It ends in a draw\n");
	}
	else if(ret == 'X')
	{
		printf("Player wins\n");
	}
	else if(ret == 'O')
	{
		printf("Computer wins\n");
	}
}
int main()
{
	int input = 0;
	srand((unsigned int)time(NULL));
	do
	{
		menu();
		printf("Please enter your operation:");
		scanf("%d",&input);
		switch(input)
		{
		case 1:
			game();
			break;
		case 0:
			printf("Game exit\n");
			break;
		default:
			printf("Please enter the correct number\n");
			break;
		}
	}while(input);
	return 0;
}

3.game.c

#include "game.h"

void InitBoard(char board[][3],int row,int col)
{
	int i = 0;
	for(i = 0;i < row;i++)
	{
		int j = 0;
		for(j = 0;j < col;j++)
		{
			board[i][j] = ' ';
		}
	}
	//memset(board,' ',row*col*sizeof(char));
}

void ShowBoard(char board[][3],int row,int col)
{
	int i = 0;
	int j = 0;
	for(i = 0;i < row;i++)
	{
		for(j = 0;j < col;j++)
		{
			printf(" %c ",board[i][j]);
			if(j < col-1)
			{
				printf("|");
			}
		}
		printf("\n");

		if(i < row-1)
		{
			for(j = 0;j < col;j++)
			{
				printf("---");
				if(j < col-1)
				{
					printf("|");
				}
			}
			printf("\n");
		}
	}
}

void PlayerMove(char board[][3],int row,int col)
{
	int x = 0;
	int y = 0;
	while(1)
	{
		printf("Please input 1-3 Coordinates:");//X
		scanf("%d%d",&x,&y);//1,1
		if(x>=1 && x<=3 && y>=1 && y <= 3)
		{
			if(board[x-1][y-1] == ' ')
			{
				board[x-1][y-1] = 'X';
				break;
			}
			else
			{
				printf("This position has been occupied.\n");
			}
		}
		else
		{
			printf("Illegal coordinate position\n");
		}
	}
}

static int IsFull(char board[][3],int row,int col)
{
	int i = 0;
	for(i = 0;i < row;i++)
	{
		int j = 0;
		for(j = 0;j < col;j++)
		{
			if(board[i][j] == ' ')
			{
				return 0;//Not full
			}
		}
	}
	return 1;//full
}

char IsWin(char board[][3],int row,int col)
{
	int i = 0;
	for(i = 0;i < row;i++)
	{
		//That's ok
		if(board[i][0]==board[i][1] 
		&& board[i][1]==board[i][2] 
		&& board[i][0]!= ' ')
		{
			return board[i][0];
		}
		//column
		if(board[0][i]==board[1][i] && board[1][i]==board[2][i]
		&& board[0][i] != ' ')
		{
			return board[0][i];
		}
		if(board[0][0] == board[1][1] && board[1][1] ==board[2][2]
		&& board[0][0] != ' ')
		{
			return board[0][0];
		}

		if(board[0][2] == board[1][1] && board[1][1] ==board[2][0]
		&& board[0][0] != ' ')
		{
			return board[0][2];
		}

		//It ends in a draw
		if(IsFull(board,row,col) == 1)
		{
			return 'Q';
		}
	}
	//No win, no draw.
	return ' ';
}

void ComputerMove(char board[][3],int row,int col)
{

	int x = 0;
	int y = 0;
	printf("Computer mobile\n");
	while(1)
	{
		x = rand()%row+1;//3  [0-3)   [1-3]
		y = rand()%col+1;
		if(board[x-1][y-1] == ' ')
		{
			board[x-1][y-1] = 'O';
			break;
		}
	}
}